A predictive model is presented to calculate moisture content of 1000-hour timelag fuels in Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) and western hemlock (Tsuga heterophylla (Raf.) Sarg.) logging slash in western Washington and western Oregon. The model is a modification of the 1000-hour fuel moisture model of the National Fire-Danger Rating System and requires daily measurements of precipitation duration, maximum and minimum relative humidities, and maximum and minimum temperatures. Comparison of measured and calculated fuel moisture contents showed good agreement. The model allows managers to accurately calculate fuel moisture values from weather variables for fuel reduction estimates. Current fire-weather stations provide adequate weather data for satisfactory operation of the 1000-hour fuel moisture model.
Ottmar, Roger D.; Sandberg, David V. 1985. Calculating moisture content for 1000-hour timelag fuels in western Washington and western Oregon. Res. Pap. PNW-RP-336. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Forest and Range Experiment Station. 16 p